You have 2 ways:
1. Use Custom Control- drop Custom Control from palette onto dialog. Switch to Edit as Text and add WS_HSCROLL and WS_VSCROLL in window styles (where WS_VISIBLE listed).
2. Use Listbox control- drop Listbox onto dialog; adjust all needed properties; switch to Edit as Text and change LISTBOX control type to your control name like TWBrowse. This will convert it to custom control storing all styles you defined for listbox.
Hope this helps.